Pasture fence device

ABSTRACT

A pasture fence device is proposed with two independent storage capacitors, which can, by means of a switching element, be discharged through the primary winding of a transformer in order to produce a HV pulse. The second storage capacitor serves to increase the pulse energy. The inventive pasture fence device is intended to ensure that the output voltage is always sufficiently high to trigger a herding shock, while keeping the energy consumption as small as possible. The invention accomplishes this by providing a second switching element (THY 2 ) to control the charging process of the second capacitor (C 2 ).

The invention relates to a pasture fence device of the type described in the preamble to claim 1.

Pasture fence devices or electric fence devices are used to keep animals in a fenced-in area. This is accomplished, in corresponding pasture fences, by pasture fence devices that feed into them high-voltage pulses which cause a herding shock when the fence is touched by an animal, and thus scare off the fenced-in animals.

Such a pasture fence device is disclosed in DE 199 62 618 B4, for example. The pasture fence device described in this publication comprises several storage capacitors which are arranged in parallel current paths for charging, and each of which is arranged in series to the primary side of the transformer. Corresponding thyristors cause an individual discharge of each storage capacitor through the primary side of the transformer, to produce a pulse on the secondary side, without changing the state of the other capacitors.

The publication U.S. Pat. No. 4,394,583 describes a pasture fence device in which a capacitor's charging voltage is controlled as a function of the load applied to the pasture fence. Although this control does make it possible for the pulse energy to be adapted to the fence situation, it also has substantial disadvantages. For example, the control is limited to an energy range of about 1:2, since the fence voltage may not fall below a minimum value in open-circuit operation, however on the other hand the capacitor's charging voltage is limited. Moreover, although a lowered voltage is normally sufficient for the fence to be able to function, relatively low values no longer guarantee that an animal's hide will be penetrated and that a sufficient herding shock will be triggered, especially in animals with thick hides.

The publication U.S. Pat. No. 5,742,104 describes a pasture fence device in which two storage capacitors can be discharged together through different primary windings. This circuit arrangement allows connection of the energy of a second storage capacitor. However, no control is provided of the energy of the connectable capacitor. It does not ensure adaptation of this pasture fence device to different fence situations.

The publication U.S. Pat. No. 4,859,868 discloses a pasture fence device in which various storage capacitors can be discharged through different windings of a transformer. This circuit allows various levels of pulse energy, however, it is very expensive, especially with regard to the transformer. In the same way, the publication EP 304 045 describes an expensive embodiment which provides two complete pulse generators.

The publication U.S. Pat. No. 6,020,658 describes a pasture fence device which has two storage capacitors whose charging voltage is synchronously controlled. This arrangement, which makes it possible to connect a capacitor and provides control of the charging voltage, gives a greater control range for the pulse energy than the prior art described above, which has a single storage capacitor. However, in this embodiment, the charging voltages of both storage capacitors are synchronously controlled together, so that here again the output voltage can be too small.

The goal of the invention is, starting from the prior art described above, to propose a pasture fence device with improved control of the pulse energy which provides an output voltage that is always sufficiently high to trigger a herding shock.

This is accomplished, starting from a pasture fence device of the type described in the preamble to claim 1, by the characterizing features of this claim.

The measures mentioned in the subordinate claims make possible advantageous embodiments and further developments of the invention.

An inventive pasture fence device comprises a first capacitor which can be discharged through the primary winding of a transformer by means of a switching element to produce a high-voltage pulse, and a second capacitor to increase the pulse energy.

Such an inventive pasture fence device is characterized in that a second switching element is provided to control the charging process of the second capacitor, and that the joint discharge of both capacitors is controlled through the first switching element.

The inventive arrangement makes it possible to control the charging of C2. In the simplest case, C2 can be connected to C1, thus increasing the device's output energy.

This principle can be further improved by providing at least one other storage capacitor. The use of at least one other storage capacitor makes it possible to adjust the device's output energy according to the capacitance of the storage capacitors used in the respective operating state. To accomplish this, it is advantageous for each storage capacitor to have a switching element associated with it to control the charging process. This makes it possible to control the charging process of one other storage capacitor or a group of other additional storage capacitors, according to the need, especially as a function of load.

In a preferred embodiment, each storage capacitor is associated with a separate switching element, so that the desired output energy of the device can be provided when the corresponding switching elements are triggered by adding the charging energy of the storage capacitors by means of the separate associated switching elements.

Moreover, open-loop or closed-loop control of the charging voltage of the second storage capacitor and/or other storage capacitors is also possible independent of the first capacitor, making it possible to charge the capacitors with different charging voltages. Thus, the charging voltage of the first capacitor ensures that the voltage of the output pulse is always sufficient, while the second and/or at least one other storage capacitor whose charging can be controlled makes it possible to vary the pulse energy within a broad range.

To accomplish this, the invention takes advantage of the knowledge that the fence voltage does not have to maintain the maximum value over the entire duration of a high-voltage pulse, but rather a high output voltage is briefly necessary to trigger the discharge causing a herding shock, while the rest of the pulse energy is completely discharged, even with lower voltage, through the corresponding fence load, e.g., an animal to be herded. Thus, the high charging voltage of the first capacitor ensures reliable triggering of the pulse discharge, while the second capacitor and/or at least one other capacitor can control the energy of the output pulse and thus the strength of the herding shock as a function of load.

An advantageous embodiment involves arranging the second capacitor and/or at least one other storage capacitor so that it/they can be discharged through the same primary winding of the transformer as the first capacitor. This considerably reduces the expense on the transformer side compared with the prior art listed above with several primary windings.

In an advantageous further development of the invention, the first and the second storage capacitors and/or at least one other storage capacitor are arranged in parallel in the transformer's primary circuit.

This allows simultaneous discharge, through a common switching device, of the first storage capacitor, the second storage capacitor, and/or at least one other storage capacitor, for which purpose a special embodiment has one or more diodes connected in parallel to the second switching element and/or at least one other switching element for at least one other storage capacitor. These diodes block the charging current of the second capacitor or the at least one other capacitor when the corresponding switching elements are in their blocked state, so that the charging process can be controlled by this/these switching element(s). By contrast, discharge of the second and/or at least one other capacitor is possible through the diode(s) even when the switching element(s) is/are in the blocked state, so that only the first switching element has to be connected for the joint discharge process of the capacitors.

In a preferred embodiment, the first switching element is arranged in such a way that after this switching element is closed, the first capacitor is discharged through the transformer's primary winding. In a certain embodiment of the invention, the second storage capacitor and/or at least one other storage capacitor are arranged parallel to the first storage capacitor through additional switching devices. As soon as the voltage of the first storage capacitor, following the closing of the first switching element, falls below the charging voltage of a second and/or at least one other storage capacitor, these switching devices turn on, and from that point on the first and the second storage capacitors discharge in parallel through the primary winding of the output transformer and the common switching element.

In another advantageous embodiment of the invention, the second storage capacitor and/or at least one other storage capacitor has a greater capacitance than the first storage capacitor, so that it is possible to control a greater range of pulse energies.

The arrangement of the second switching element and/or at least one other switching element offers the advantage of making it possible to charge the second storage capacitor and/or at least one other storage capacitor separately from the first storage capacitor by using the associated switching element(s) either to connect the ground connection of the second storage capacitor and/or at least one other storage capacitor to the circuit's ground, or to separate it from the ground.

Accordingly, the invention provides a controller which can separately activate the first and the second switching elements, and possibly at least one other switching element for at least one other storage capacitor. This makes it possible to charge the first storage capacitor up to maximum voltage at first, and then, by activating the second switching element, to charge up the second storage capacitor, and/or by activating one or more other switching elements, to charge up one or more other storage capacitors to a value which lies between zero and the voltage on the first storage capacitor.

It is noteworthy that this type of circuit configuration, with its charging process in which the capacitors are charged one after the other, gives the inventive circuit configuration an especially simple structure.

In a certain embodiment of the invention, the charging voltage of the second capacitor and/or one or more other storage capacitors is controlled as a function of load, while the first capacitor is always charged to maximum voltage.

To accomplish this, it is preferable to provide a high-voltage sensor which measures the load applied to the pasture fence, i.e., the impedance to the ground. The controller can then control the charging voltage of the second capacitor and/or one or more other storage capacitors as a function of the size of this fence load.

In a certain embodiment of the invention, the second and/or at least one other storage capacitor are connected in to the charging process and/or the discharge process as a function of load. This embodiment makes it possible to put together the desired load-dependent output energy of the device by adding together the energy which can be stored in individual capacitors. Moreover, the timing of when the individual capacitors are connected in and their charging process allows the time behavior of the device's output voltage to be flexibly adjusted within a broad range.

In an especially simple but effective embodiment of the invention, all capacitors provided for producing the desired output energy are always completely charged by connecting them in during the discharge process. When this is done, the joint discharge can, as in the previously described embodiment, be jointly fed by switching the discharge process into the primary coil of the transformer through a single switching element. This embodiment makes it possible to put together the output energy in energy quanta, so to speak, with a single quantum being the capacitance of each individual storage capacitor.

Using more than two storage capacitors makes it possible for the reserve energy needed after the triggering process to be provided and called upon in small units at high voltage. For example, it is possible to produce a high, almost uniform voltage as a function of load, while simultaneously consuming little current.

A sample embodiment of the invention is shown in the drawing and is explained in detail below by the description.

In particular, the figures are as follows:

FIG. 1 shows a circuit diagram of an example of the inventive pasture fence device; and

FIG. 2 shows a pulse diagram produced by a certain embodiment of the invention.

A supply of power is controlled by a controller. External inputs make it possible for the controller to be adjusted or programmed.

The power supply provides the charging voltage for two storage capacitors C1 and C2 through a voltage converter, i.e., a direct current converter (DC-DC) or an alternating current converter (AC-DC).

Storage capacitor C1 is charged through diodes D2 and D6, while storage capacitor C2 is charged through diodes D2 and D1. This makes charge equalization from C1 to C2 impossible, so that C2 can be charged at a lower voltage than C1.

In the circuit of the primary winding of transformer TR1, capacitor C1 has a thyristor THY1 arranged next to it, which can be triggered through the controller.

L1 and C3 are pulse-shaping elements which are used, in a manner known in the art, to suppress high-frequency components in the output side pulse.

When thyristor TH1 is triggered, the charged up storage capacitor C1 is discharged through transformer TR1, sending to the secondary winding an output-side high-voltage pulse, which is delivered to fence Z. When the fence is touched by the corresponding animal, the high-voltage circuit is closed through the ground (GND).

A high-voltage sensor (HV sensor) detects the fence load or impedance with respect to the ground. If there is a voltage sensor as described above, it detects the maximum voltage, which depends on the fence load. In this way, the fence load applied to fence Z is transmitted to the controller.

The second storage capacitor C2 is connected, through the diodes D4 and D5 which serve as switches, in parallel to the first storage capacitor C1 in its discharge circuit. Since the first capacitor C2 is always charged with a high voltage, e.g., its full charging voltage, at first it discharges through the primary winding of transformer TH1 until it has been discharged to the charging voltage of the second storage capacitor C2. Now D4 and D5 are conducting, and from that point on both capacitors C1 and C2 discharge together through transformer TR1.

FIG. 2 shows a diagram of a possible sequence of pulses which is possible with the circuit configuration shown in FIG. 1.

In this diagram the X-axis represents time (T), and the Y-axis represents the output voltage, that is the fence voltage HV.

Pulse I which has voltage HV1 while no load is applied to fence Z, is produced by storage capacitor C1 alone: In this case C2 is not charged, since switching device THY2 remains blocked during the charging process.

As soon as a breakdown occurs, the voltage suddenly collapses to a value that depends on the load. This process is shown in pulse II.

The HV sensor allows the controller to detect the behavior of the voltage and to control, through the second switching element THY2, the charge of C2 according to the load. If the voltage falls below a minimum value under load, the charging voltage of C2 is correspondingly increased.

Pulse III shows the discharge process following a change in load, in which storage capacitor C2 is charged up to a higher charging voltage. At first the same voltage behavior results as in pulse II, since at first only the first storage capacitor C1 is discharged here (III.1).

Following that, in pulse phase III.2 both storage capacitors C1 and C2 are discharged together, and the voltage applied to the load is now higher and it is applied longer. The area under the pulse curves shown is now significantly larger. This is a measure of the energy which is delivered to a certain load, that means the shock energy increases when there is a load.

The inventive device makes possible a very great control range of pulse energy. However, at the same time it ensures that an output voltage HV2 is always reached, which corresponds to the breakdown voltage for triggering the discharge process. Taken together, the two effects provide high herding security, first since the voltage or current pulse triggering a herding shock when an animal touches the fence is reliably triggered, and second since the pulse continues to have the appropriate energy to ensure a sufficiently great herding shock to scare off the animal.

Despite the simple structure of an inventive circuit, which is shown from the sample embodiment in FIG. 1, it makes possible great herding security with little consumption of current in open-circuit operation and continuously variable control of the pulse energy, independent of the open-circuit voltage.

However, the circuit shown in FIG. 1 represents only one specific embodiment of the invention, and the invention is not limited to this specific embodiment. An essential element of the invention is the second switching element, which is provided to control the independent charging process of the second storage capacitor. 

1. Pasture fence device with a first storage capacitor, which can, by means of a switching element, be discharged through the primary winding of a transformer in order to produce a HV pulse, with a second storage capacitor provided to increase the pulse energy, characterized in that a second switching element (THY2) is provided to control the charging process of the second storage capacitor (C2).
 2. Pasture fence device of claim 1, characterized in that at least one other storage capacitor is provided.
 3. Pasture fence device of one of the preceding claims, characterized in that each storage capacitor has a switching element associated with it to control the charging process.
 4. Pasture fence device of one of the preceding claims, characterized in that each storage capacitor has a separate switching element associated with it.
 5. Pasture fence device of one of the preceding claims, characterized in that the second storage capacitor (C2) and/or at least one other storage capacitor have a charging process of which is independent of the first capacitor (C1).
 6. Pasture fence device of one of the preceding claims, characterized in that the second storage capacitor (C2) and/or at least one other storage capacitor can be discharged through the same primary winding of the transformer (TR) as the first storage capacitor (C1).
 7. Pasture fence device of one of the preceding claims, characterized in that the first storage capacitor (C1), the second storage capacitor (C2), and/or at least one other storage capacitor are arranged in parallel in the discharge circuit of the transformer (TR).
 8. Pasture fence device of one of the preceding claims, characterized in that the first storage capacitor, the second storage capacitor, and/or at least one other storage capacitor are connected to the discharge circuit through a common switching element (THY1).
 9. Pasture fence device of one of the preceding claims, characterized in that one or more diodes is/are connected in parallel to the second switching element (THY2) and/or at least one other switching element for at least one other storage capacitor.
 10. Pasture fence device of one of the preceding claims, characterized in that a controller is provided for separate activation of the first switching element (THY1), the second switching element (THY2), and/or at least one switching element for the other storage capacitor(s).
 11. Pasture fence device of one of the preceding claims, characterized in that the second switching element (THY2) and/or at least one switching element for at least one other storage capacitor is/are connected in for the charging process of the second storage capacitor (C2).
 12. Pasture fence device of one of the preceding claims, characterized in that the charging voltage of the second storage capacitor (C2) and/or at least one other storage capacitor can be controlled as a function of load.
 13. Pasture fence device of one of the preceding claims, characterized in that the second storage capacitor and/or at least one other storage capacitor can be connected in to the charging process and/or the discharge process as a function of load.
 14. Process to operate a pasture fence device of claim 1, characterized in that the energy charged in storage capacitor (C2) and/or at least one other storage capacitor can be controlled as a function of load.
 15. Process of claim 14, characterized in that the first storage capacitor (C1) is charged up independent of the load.
 16. Process of claim 14 or 15, characterized in that it provides joint discharge of the first storage capacitor (C1) and second storage capacitor (C2) and/or at least one other storage capacitor.
 17. Process of one of claims 14 through 16, characterized in that the second storage capacitor and/or at least one other storage capacitor are connected in the charging process and/or the discharge process as a function of load. 